I currently trying to convert a Silvertone radio mo.# 101.860-2 into a guitar amp.

Ran across some interesting voltage readings in the the power section. Can anyone explain why my 7z4 rectifier tube is getting about 230voltsDC on the plates and yielding 500voltsDC on the cathode when the amp schematic say 212volts. What gives any ideas?????

I guess I understand that the voltage should be larger on the cathode but why so out of spec? There is only one cap between the cathode of the rectifier to the primary on the OT. Why would the voltage be so much higher than spec.